CASH DISTRIBUTIONS (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2012 General Partner	Dec. 31, 2011 General Partner	Dec. 31, 2010 General Partner	Dec. 31, 2012 General Partner Incentive Distribution, as amended $0.81 per common unit	Dec. 31, 2012 General Partner Incentive Distribution, as amended $0.88 per common unit
CASH DISTRIBUTIONS
Number of days after the end of each quarter for making cash distribution									45 days
Quarterly cash distributions (in dollars per unit)									$ 0.78
Cash Distributions
Combined general partner interest and incentive distribution interest percentage of quarterly distributions of Available Cash exceeding target levels, threshold													15.00%	25.00%
Target level of quarterly distributions (in dollars per common unit)													$ 0.81	$ 0.88
Cash distributions (in dollars per unit)										$ 3.10	$ 3.04	$ 2.94
Cash distribution	$ 43	$ 43	$ 42	$ 42	$ 42	$ 42	$ 35	$ 35		$ 169	$ 155	$ 139
Percentage of priority income allocations for incentive distributions										100.00%